model-auth.js

const router = require('restify-router').Router;
const routes = new router();

const AuthController = require('../controller/auth');

routes.post('/login',AuthController.login);
routes.get('/logout',AuthController.logout);
routes.get('/session',AuthController.session);

//return the restify-router instance
module.exports = routes;

model-cart.js

const router = require('restify-router').Router;
const routes = new router();

const CartController = require('../controller/cart');

routes.get('/',CartController.getCart);
routes.post('/addProduct',CartController.addProduct);
routes.delete('/removeProduct',CartController.removeProduct);

//return the restify-router instance
module.exports = routes;

model-index.js

//The index.js should not have much logic. Only build the version of the API and assign controller.

const router = require('restify-router').Router;

//returns restify-router instance
const product = require('./product');
const cart = require('./cart');
const auth = require('./auth');

module.exports = (app) => {

  //setup a router for v1 & v2 and 
  //add all controllers that are the same in both versions
  const basicRouter = new router();
  
  //auth and product are the same in v1 & v2
  basicRouter.add('/auth', auth);
  basicRouter.add('/product', product);
  
  //setup the v1
  const apiV1 = new router();
  
  //copy/merge basic router to v1
  apiV1.merge(basicRouter);
  
  //Add additional controllers to v1 
  //These controllers are only available in v1
  apiV1.get('/foo', foo);
  
  //bind apiV1 to app/server and set prefix
  apiV1.applyRoutes(app, '/api/v1');
  // GET /api/v1/product/:id
  // GET /api/v1/cart/ -> notFound / it´s a v2 restricted endpoint
 
  
  //setup apiV2
  const apiV2 = new router();
  //merge/copy basic router as in v1
  apiV2.merge(basicRouter);
  //Add additional controllers to v2 
  //These controllers are only available in v2 (not in v1)
  apiV2.add('/cart',cart);
  apiV2.get('/foo', bar);
  //bind v2 to app/server and set prefix
  apiV2.applyRoutes(app, '/api/v2');
  // GET /api/v2/cart/
  // POST /api/v2/auth/login -> same as POST /api/v1/auth/login
  
  //setup v3
  const apiV3 = new router();
  //v3 is v1 + v2
  //last set overwrite existing method
  apiV3.merge(apiV1,apiV2);
  //v1 & v2 have POST /auth/login
  //merge apiV1 will set first POST /auth/login and be overwritten by apiV2 with the same controller
  //v1 & v2 have GET /foo but different controller (v1/foo | v2/bar)
  //By merging v2 after v1, GET /foo will return the v2/bar controller, because this has overwritten the v1/foo controller
  
  //bind v3 to app/server and set prefix
  apiV3.applyRoutes(app, '/api/v3');
  // GET /api/v3/cart/ the v2 restricted endpoint in v3
  // POST /api/v3/auth/login -> same as POST /api/v2/auth/login -> same as POST /api/v1/auth/login
  // GET /api/v3/foo -> same as /api/v2/foo -> NOT same as ->/api/v1/foo (v1 replaced by v2) 
  
  
  
};

model-product.js

const router = require('restify-router').Router;
const routes = new router();

const ProductController = require('../controller/product');

routes.get('/:id',ProductController.getProduct);
routes.post('/add',ProductController.addProduct);

//return the restify-router instance
module.exports = routes;

router-clone.js

//merge is combine existing endpoints with new endpoints
//clone JUST copy the router

//v1 is a restify-router instance like model-product.js
const v1 = require('./v1.0_router');
v1.get('/foo', (req,res,next) => {});

const v1_1 = v1.clone().merge(require('./v1.1_router'));
//same as
const v1_1 = new router();
v1_1.merge(v1);
v1_1.merge(require('./v1.1_router'));
                   
                   
//copy all from v1.0 to v1.1
const v1_1 = v1.clone()
//add new endpoints from 1.1 and (if in v1.1 also exists) overwrite v1.0 endpoints
v1_1.merge(require('./v1.1_router'));

//v1_1 new router() not required, because its copied from 1.0
//in short
const v1_1 = v1.clone().merge(require('./v1.1_router'));

//full
const v1_1 = v1.clone().merge(require('./v1.1_router')).applyRoutes(app,'/api/v1.1');